什麼是彌爾的方法

彌爾在他的《邏輯學體系》（System of logic, 1843）所區辨出來的五種實驗推論的方法。假設有個人，對於在一組特定的條件下，對於決定，什麼因素在引起特定的結果（稱為結果E）中所扮演的角色，感到有興趣。一致性的方法告訴我們，要去尋找，出現在所有結果E發生的情況下的因素。差異性的方法告訴我們，要去尋找某些在結果E發生的情況下的因素，以及當結果E並未發生的另一個相似情況下所欠缺的某些因素。一致性與差異性的聯合方法，結合前兩種方法。殘餘（residues）的方法應用在，當結果E的部分，可藉指涉已知的因素加以解釋；這個方法並告訴我們，將「殘餘」歸之於其餘當結果E發生的條件。相伴變項的方法，則是運用在當結果E能夠以不同的程度出現時；如果我們確認一個因素F，諸如氣溫，它的變項與結果E的變項，如尺寸，有正相關或負相關的關係。而後我們能夠指出因素F在因果上與結果E相關連。

Mill's methods

Five methods of experimental reasoning distinguished by John Stuart Mill in his System of Logic (1843). Suppose one is interested in determining what factors play a role in causing a specific effect, E, under a specific set of circumstances. The method of agreement tells us to look for factors present on all occasions when E occurs. The method of difference tells us to look for some factor present on some occasion when E occurs and absent on an otherwise similar occasion when it does not. The joint method of agreement and difference combines the two previous methods. The method of residues applies when part of E is explicable by reference to known factors, and tells us to attribute the "residue" to the remaining circumstances under which E occurs. The method of concomitant variation is used when E can be present in various degrees; if we identify a factor F, such as temperature, whose variations are positively or negatively correlated with variations in E, for instance, size, then we can infer that F is causally connected with E.